The present invention relates to nutritional support for patients suffering from cancer cachexia. More particularly, the present invention concerns a method for providing total parenteral nutrition for cancer cachexia patients which yields improved nitrogen balance, improved plasma albumin levels, and decreased glucose clearance as compared with conventional total parenteral nutrition.
Cancer cachexia syndrome is characterized by reduced dietary intake and progressive weight loss, primarily, but not exclusively, through the loss of skeletal muscle and adipose tissue. Cancer cachexia syndrome is found in association with a number of conditions, e.g., after surgery or radiotherapy for malignancy, or mechanical obstruction of the gastrointestinal tract as in esophageal cancer.
Use of total parenteral nutrition can ameliorate the problem of reduced dietary caloric intake in cancer cachexia patients but the use of conventional total parenteral nutrition formulas appears to replete fat stores rather than saving and/or restoring lean muscle tissue. These conventional total parenteral nutrition formulas consists primarily of either carbohydrates, e.g., glucose, or long chain triglycerides (LCT), e.g., safflower and/or soybean oil. However, carbohydrate diets can lead to insulin problems while LCT diets lead to fat deposition in the liver, impair leukocyte chemotaxis and random migration, and interfere with the function of reticuloendothelial system function.
In order to overcome these problems, medium chain triglycerides (MCT) have been tried as a source of total parenteral nutrition in certain conditions, e.g., liver disfunction. MCT's are formed from saturated fatty acids with chain lengths of 6-12 carbons, primarily 8-10 carbons, linked to a glycerol backbone. MCT's have a unique metabolism which has advantages for total parenteral nutrition; they are rapidly absorbed by the body through the portal system without initial intestinal hydrolysis. In contrast, LCT's require initial hydrolysis and absorption by the lymphatic system before they can be utilized as an energy source. Moreover, MCT's cause fewer fat deposits in the liver and are much more rapidly used as an energy substrate. Because of this, enteral and parenteral applications for MCT diets have been proposed. See Bach and Babyan in "Medium-Chain Triglycerides: Update," Am.J.Clin. Nutrition 36, pp. 950-962, November 1982.
However, there have been problems reported with the use of high levels of MCT's in diet. Intravenous administration of large quantities of MCT's in dogs or rats has produced somnolence, vomiting, coma and death. Because the MCT's are digested in the liver, liver disfunction patients may also not be good candidates for MCT therapy. To counter act these potential problems, as well as fulfilling the need for certain amounts of .omega.6 fatty acids, e.g., linoleic acid, required for proper metabolic functioning, physical mixtures of LCT's and MCT's, as well as structured lipids having medium chain fatty acids and long chain fatty acids on the same glycerol backbone, have been used. In fact, both physical mixtures and structured lipids have been used as total enteral or parenteral nutrition for hypercatabolic patients. See U.S. Pat. No. 4,528,197, assigned to KabiVitrum, Inc.; DeMichele et al., "Effect of Total Enteral Nutrition with Structured Lipids of Protein Metabolism in Thermally Injured Rats," Fed.Proc. 46:1086 (1987); and U.S. Pat. No. 4,703,062, assigned to Baxter-Travenol, Inc.
Although there are some similarities between hypercatabolic states and cancer cachexia, they are clinically distinct. For example, hypercatabolic patients uniformly show increased losses of body protein, as reflected in urinary nitrogen excretion. In contrast, patients with cancer cachexia often show a positive rather than negative nitrogen balance. See Bistrian, "Some Practical and Theoretical Concepts in Nutritional Assessment of the Cancer Patient," CANCER 58(8):1863-1866 (1986). Therefore, treatments effective for hypercatabolic states may not be appropriate for cancer cachexia.
Accordingly, an object of the invention is to provide a method for supplying nutrition to cancer cachexia patients which spares lean muscle and adipose tissue.
Another object of the invention is to provide total parenteral nutrition for cancer cachexia patients.
A further object of the invention is to provide a method of improving nitrogen balance, plasma albumin levels, and glucose clearance rates in cancer cachexia patients.
These and other objects and features of the invention will be further described in the description and the drawings.